If it's like the Helios 44-2, it'll flare like no-one's business and will have less contrast. However, it's a shame to hear about the loss of sharpness past T4; the Helios 44-2 maintains a decent sharpness wide open at a F2.

That being said, I think you're better off with the Sony.

Of course, you can look into the Helios 44-2 58mm for like $20 and a Jupiter-9 85mm for like $100! You can't put them on a PL, but are excellent glass nonetheless.